org 07c00h
mov ax,cs
mov ds,ax
mov es,ax
call DispStr
jmp $
DispStr:
    mov ax,BootMessage
    mov bp,ax
    mov ax,01301h
    mov bx,000ch
    mov dl,0
    int 10h
    ret
BootMessage: db "Hello,OS world!"
times 510-($-$$) db 0
dw 0xaa55
